Effects of carbon dioxide anaesthetic on Glossina.

Exposure of 2 day old virgin females of Glossina fuscipes fuscipes, G. pallidipes, G. brevipalpis, and G. morsitans centralis to carbon dioxide anaesthesia for 15 sec has the effect of suppressing their subsequent insemination frequency. This insemination-inhibitory effect of the gas is more pronounced in G. f. fuscipes and G. pallidipes than in G. brevipalpis and G. m. centralis. In G.f. fuscipes the adverse effect on insemination persists, albeit to a lesser degree, at least up to 72 hr. Carbon dioxide anaesthesia also reduces the insemination capability of G.f. fuscipes males; this effect, however, is less marked than in females. Exposure of wild non-teneral G.f. fuscipes, G. pallidipes, G. brevipalpis, and 3 day old G.m. centralis to the gas for 30 min causes some mortality during anaesthesia, which increases with increasing exposure period. G. m. centralis is most tolerant to the lethal effect of the gas within the 10-90 min exposure periods. Wild females of G.f. fuscipes and G. pallidipes seem to be more sensitive to carbon dioxide in this report than males. In view of these adverse effects produced by carbon dioxide anaesthesia, its use on tsetse is not to be recommended.